In testing bacteria with respect to a specimen, a method of culturing the bacteria in a culture medium within a petri dish and harvesting the bacteria has been used. In this method, in general, a suspension of the bacteria is smeared to the culture medium and the bacteria are cultured in a constant-temperature bath and thereafter, optically visually observed, and a target bacterial colony is harvested. The harvested bacteria are used for the purpose of testing antibiotic tolerance. A method of testing the antibiotic tolerance of the bacteria is disclosed in detail in Patent Literature 1. In a minimum inhibitory concentration (MIC) method, a diluted liquid of an antibiotic substance is injected into a liquid medium or a solid medium, the harvested bacteria colony the medium with the harvested bacterial colony, and a growing condition of the bacteria is observed by culturing the bacteria. A culturing condition is observed in a plurality of media by variously changing the concentration of the diluted liquid of the antibiotic substance, thereby making it possible to acquire a minimum antibiotic substance concentration which cannot be grown and an appropriate drug concentration capable of reducing a burden to a patient can be determined.
Meanwhile, Patent Literature 2 discloses a bacterial colony transferring apparatus in which a bacterial colony within a petri dish is photographed with a television camera, a tester visually verifies an image projected on a monitor and indicates a bacterial colony to be harvested to automatically move a pick-up to the position of the bacterial colony, harvests the bacterial colony, and transfers the harvested bacterial colony to a test tube.
Further, Patent Literature 3 discloses a method of analyzing a result of harvesting using filtering after liquefying a specimen with a Fourier transform infrared spectrophotometer (FT-IR) or a microscopic infrared spectrophotometer and comparing a waveform of spectral absorbance with a waveform registered in a database to identify the waveform.
A microbial analysis apparatus is used to, in testing a specimen in a medical practice, identify a species of a microorganism included in the specimen and measure susceptibility of the microorganism to an antibiotic. Establishing a therapeutic measure by determining a kind and a concentration of a drug which is effective with respect to the microorganism detected from the specimen is very important to perform appropriate antimicrobial therapy.
Herein, one example of a flow of testing a specimen will be described below. First, collected specimens (for example, blood, sputum, feces, and the like) are dyed and observed with a microscope. When a positive reaction is observed, the specimens are moved onto a medium (for example, agar, and the like) of a petri dish and the petri dish is inputted into an incubator. One day after, when the petri dish is extracted from the incubator, a plurality of kinds of bacterial colonies of microorganisms are generated on the medium. One kind of microorganism is selected and harvested among the plurality of kinds of bacterial colonies and moved to the test tube and bacterial liquids having a plurality of kinds of concentrations are adjusted by adjusting the concentration thereof with normal saline. The bacterial liquids adjusted to the plurality of kinds of concentrations are inputted into a microorganism testing apparatus, and identification of bacteria and drug susceptibility are examined.
In order to rapidly and accurately test the specimen, a microorganism analysis apparatus that automates each work is proposed. For example, Patent Literature 4 discloses an automatic analysis apparatus of bacteria. The automatic analysis apparatus of bacteria disclosed in Patent Literature 1 includes a test liquid preparing unit, a pre-incubation, a top agar dispensing unit, a plating unit, a plate receiving unit, a bacterial colony counting unit, a data processing unit, a test tube transferring means, and a plate receiving rack transferring means and can automatically perform a series of analysis operations of counting the number of bacterial colonies with high precision in preparing the test liquid.
Patent Literature 5 discloses a microorganism screening apparatus including an image processing apparatus detecting a position of a bacterial colony, an elevator unit transferring a work with a rotating operation mechanism and an ascending and descending operation mechanism, a harvesting/inoculating unit that performs harvesting and inoculating while determining harvesting and inoculating positions by operating a robot, a work transporting unit moving and transporting the work, a cover opening/closing unit controlling opening/closing a cover of the work, a liquid dispensing unit performing dispensing of a liquid medium, an agar dispensing unit dispensing an agar medium, and a host computer unit performing control operations such as management of data of microorganism resources, a command of an operation mode, and the like. The microorganism screening apparatus disclosed in Patent Literature 5 aims at automating various operations required for screening a soil microorganism and further, improving reliability by completely managing a strain and data.
Patent Literature 6 discloses a method and an apparatus for testing a microorganism colony. The method and apparatus for testing the microorganism colony disclosed in Patent Literature 6 may compare an image of a petri dish, an image before a bacterial colony is generated, and an image after the bacterial colony is generated, remove contamination of a photographing system or a residue on a medium from the image after the bacterial colony is generated, and accurately count the number of bacterial colonies. It is described that, by combining a mark printed on the petri dish with each image in advance, the images may be accurately compared with each other.
Patent Literature 7 discloses a method and an apparatus for collecting a bacteria colony. The method and apparatus for collecting a bacteria colony disclosed in Patent Literature 7 aims at installing a position reference means of a bacterial colony, determining an absolute spatial position of the bacterial colony, and accurately determining a place of a harvested bacterial colony.
In infectious disease therapy, establishing a therapy measure by identifying mastoiditis, rapidly measures susceptibility to antibiotic, and determining an effective drug is important for appropriate antimicrobial therapy. In general, a presented specimen is applied to a medium and cultured, bacterial suspension is prepared by harvesting the generated bacterial colony and suspending the harvested bacterial colony to normal saline, and the bacterial suspension is inoculated into a measuring device of an identification and drug susceptibility testing apparatus. In identification and susceptibility testing, it is required to make the amount of bacteria inoculated into the device constant at predetermined concentration with accuracy and high reproducibility, in order to acquire an accurate result. In most cases, in order to acquire a predetermined amount of bacteria, a plurality of same kinds of bacterial colonies are selected and harvested among bacterial colonies grown on a petri dish, suspended to a liquid such as normal saline within one vessel, and prepared with a predetermined concentration (the number of bacteria) by measuring turbidity or opacity. Kinds of mixed bacterial colonies should be the same as each other and a plurality of kinds of bacterial colonies are generally grown on the same petri dish, and a high-level technique is required of a laboratory technician in selecting the same kind of bacterial colonies among them. Further, since the same kind of bacterial colonies are selected from various large and small-sized bacterial colonies, it is required that turbidity is first adjusted and thereafter, the bacterial colonies are added or normal saline for dilution is added in order to acquire predetermined turbidity, and as a result, it is complicated and it takes some time. Therefore, the method and apparatus for collecting a bacteria colony are not appropriate to mass processing. As a related art to make the amount of harvested bacteria per one time constantly, a simple kit has been commercialized, which can acquire a predetermined concentration of bacterial liquid by harvesting a predetermined amount of bacteria and suspending the harvested bacteria to a predetermined amount of normal saline. For example, a method disclosed in Patent Literature 8 discloses an example capable of collecting a predetermined amount of bacteria by using a simple stick body with a groove. However, in this method, a concentration and the amount of bacterial liquid acquired are limited, and as a result, only a small amount of bacterial liquid with a comparatively low concentration range can be acquired.
Meanwhile, Patent Literature 2 discloses, as a bacterial colony transferring apparatus, a method in which the bacterial colony within a petri dish is photographed with a television camera, the laboratory technician visually verifies an image projected on a monitor and selects and indicates a bacterial colony to be harvested to automatically move a harvesting tool to the position of the bacterial colony according to the indication, harvest the bacterial colony, and transfer the harvested bacterial colony to a test tube. However, in this method, the image which the laboratory technician photographs by using the television camera is verified through the monitor to select the harvested bacterial colony one by one, and as a result, even though the apparatus is used, an effect of rapidity is slight.
Similarly, Patent Literature 9 and Patent Literature 10, as the bacterial colony transferring apparatus, discloses a method in which a laboratory technician verifies an image photographed by a television camera through a monitor, inputs a condition such as the size of a bacterial colony to be selected or indicates a bacterial colony to be excluded, and as a result, a bacterial colony to be harvested is automatically transferred to a new medium. In this method, the bacterial colonies grown on the petri dish are basically all the same bacterial species and all bacterial colonies other than an exception grown by contamination and the like are transferred, and since the apparatus is unmanly operated by inputting only a condition, significant power saving is achieved. However, by harvesting the bacterial colony one by one from the petri dish before transferring and transferring the bacterial colony to a medium of a new petri dish one by one, the bacterial colony need not be mixed, and as a result, a type of the bacterial colony is not discriminated.
In preparing the bacterial liquid for identification testing or drug susceptibility testing intended in the present invention, a plurality of same kind of bacteria needs to be harvested from one petri dish and different kinds of bacteria need to be excluded and only a single kind of bacteria needs to be selected from the image acquired by the television camera. However, since a comprehensive feature of the bacterial colony cannot be normally extracted by only one image acquired by using the television camera, an error may occur when the bacterial colony is selected. Meanwhile, a bacterial colony counter that measures the number of bacterial colonies including bacterial colonies on the agar medium as well as the surface of the petri dish has been available in the market. This processes a 2D image photographed by the camera and measures the number of bacterial colonies having a size larger than a size suitable for the condition and similarly, cannot discriminate different kinds of bacterial colonies. In the above example, the acquired image is based on plane information and the size of the bacterial colony can be measured, but information on a shape or a height direction of the bacterial colony cannot be acquired.